Leone-Liberian Upland

an upland in West Africa in the Republic of Guinea, Sierra Leone, and Liberia. It extends from the northwest to the southeast, descending in a series of scarps to the coastal lowlands of the Atlantic Ocean and sloping gently into the heart of the mainland. The upland is composed of Precambrian granites, gneisses, schists, and quartzite, breached by intrusions of basic rock. Numerous domal, island mountains and mountain ridges, consisting of particularly hard rock, ascend steeply over the plateau-shaped, slightly curving surface of the upland (average elevation is 500–800 m). The summits of Mount Bintinami (1,948 m) and Mount Nimba (1,752 m) are the highest points. The extremely humid southeastern slopes of the upland are covered with dense, humid evergreen forests; the opposite, dryer slopes are populated by tall-grass savannas with islets of deciduous and evergreen forests and by sparse, deciduous savanna forests. There are large deposits of iron ore (Mount Nimba), gold, diamonds, and bauxite.